Re: Is BP the right plattform for my project?
Sounds to me like most of your requirements could be met with WP Multisite plus a few selected plugins and themes.
– P2 allows for front-end posting
– https://wordpress.org/extend/plugins/more-privacy-options/ expands WP’s default privacy options to allow blog admins to hide their blogs from everyone but themselves
– Forums could be accomplished with bbPress or a forum-specific WP plugin
Depending on what you need out of “blogs”, you might also be able to repurpose BuddyPress groups to do something similar. For instance:
– Each member is the sole member of a private/hidden group, and uses BP activity to “blog”. Since this happens through BP, there is no WP Dashboard involved.
– Likewise with Notes
– Depending on what you want with “Link List”, that can be pretty easily done with an additional profile field.
– Forums would of course be built in, in the form of non-private groups that the user could join.
How to decide? If you don’t need the rich functionality of blogs (post revision history, out of the box multimedia support, etc), then actually giving each user two WP blogs might be too much overhead. In that case, BP would be a good choice. The functionality that you’d need is all already there; your work would be limited to customizing and configuring the interface.